Manufacturing photographic film packets

ABSTRACT

IN MANUFACTURING FILM PACKETS A UNITARY WEB IS CENTRALLY SLIT INTO TWO IDENTICAL STRIPS WHICH ARE REJOINED BY A NARROW TAPE. PREFERABLY, THE WEB IS SIMULTANEOUSLY CUT CENTRALLY AND ALONG ITS MARGINS AND A SECOND TAPE IS ADHERED TO THE WEB OVERLAPPING ONE OF ITS MARGINS.

Jan. 12,. 1971 L. L. LEINONEN 3,554,838

' MANUFACTURING PHOTOGRAPHIC FILM PACKETS Filed Dec. 12, 1968 2 Sheets-Sheet 1 Jam'lz", 197.1 LElNONEN 3,554,838

MANUFACTURING PHOTOGRAPHIC FILM PACKETS Filed Dec. '12, 1968 2 Sheets-Sheet z United States Patent 3,554,838 MANUFACTURING PHOTOGRAPHIC FILM PACKETS Leonard L. Leinonen, Framingham, Mass., assignor to Polaroid Corporation, Cambridge, Mass., a corporalion of Delaware Filed Dec. 12, 1968, Ser. No. 783,359 Int. Cl. B32b 31/00 US. Cl. 156-259 1 Claim ABSTRACT OF THE DISCLOSURE In manufacturing film packets a unitary web is centrally slit into two identical strips which are rejoined by a narrow tape. Preferably, the web is simultaneously cut centrally and along its margins and a second tape is adhered to the web overlapping one of its margins.

This invention relates to photographic film packets.

Objects of the invention are to provide such packets that meet high dimensional tolerances during the process of their manufacture and retain a flat configuration (e.g., despite humidity changes which might otherwise buckle and envelope) until used, all without special preparation (e.g., humidity conditioning, high dimensional accuracy) of the raw web material from which the packets are made and with minimum manufacturing cost and complexity.

In general the invention features longitudinally cutting a unitary web centrally into two identical strips of known width and adhering a narrow tape to the slit web along the resulting central out. In preferred embodiments the web is simultaneously cut centrally and along its lateral margins; the tape is pre-creased along its centerline; the web is cut with continuously rotating circular knives; and a second tape is adhered to the web overlapping one of its margins.

Other objects, features and advantages will appear from the following description of a preferred embodiment of the invention, taken together with the attached drawings thereof, in which:

FIG. 1 shows a film packet;

'FIG. 2 is an isometric view of machinery useful in practicing the invention;

FIG. 3 is an end view of the web slit assembly thereof; and

FIG. 4 is an end view of the side tape laminator assembly thereof.

FIG. 1 of the drawings shows a film packet generally designated 10, including two outer walls 14 and 16 composed of opaque paper stock. The walls are fastened together along their longitudinal edges by folded binding side tapes 18 and 20 composed of an opaque polyethylenecoated paper. Various photographic components are inside the packet, and a clip 22 is attached at one end.

Web slit assembly 32 is provided to form sheets 14 and 16 from a single web 30 of paper stock, and includes a knife blade sub-assembly 44 (FIG. 3) and anvil subassembly 46. Knife blade sub-assembly 44 includes a rotatable shaft 50 on which are mounted three circular knife blades 52, equally spaced. Anvil sub-assembly 46 includes a rotatable shaft '60 on which are mounted three circular anvils 62 spaced to correspond to knife blades 3,554,838 Patented Jan. 12, 1971 ice 52 and having ground shearing edges 64 cooperating with blades 52 to form a cutting unit. Knife blade sub-assembly 44 is retractable by means not shown.

Side tape laminator assembly 34 includes heads 63 and mounted on movable pistons 66 and 68, respectively, in C-frame 70, and carrying heated laminators 71, 72, 73, and 74 each longer than the length of packet 10. Side tapes 18 and 20, each precreased along its longitudinal center line, are fed (by means not shown) over idler rollers 84, 85, to the underside of the web between laminators 71, 72, 73, 74.

In operation web 30 is advanced through the machine, intermittently, in packet-long lengths, by means not shown. The width of the web is greater than the sum of the widths of the finished walls 14 and 1'6 and need not be precisely controlled. As the web passes between knives 52 and anvils 62 it is cut at its margins and along its centerline into two equally wide strips 30a and 30b which will eventually form walls 14 and 16. The knives and anvils rotate continuously, even when the web is stopped between its intermittent movements, simplifying the control system for the apparatus. Strips 30a and 30b are of the exact width desired for passage through the remainder of the packet forming apparatus. After passing between the knives and anvils, the web 30, now travelling as two parallel strips 30a and 30b, passes through the side tape laminating assembly 34.

One tape, 20, is guided to under the junction of web strips 30a and 30b, the length of tape being parallel to the slit between strips 30a and 30b, and overlapping each web strip about equally.

The other tape, 18, is guided to under the outer edge of web strip 30a about half the width of tape 16 overlapping strip 30a, and the other half extending beyond the edge of strip 30a.

Each time the web stops after movement through the length of one packet, heads 63 and 65 are moved by pistons 66 and 68 toward the web strips and side tapes so that laminators 71, 72, 73, and 74 may heat seal the tapes to the web strips. The overlapping laminations as sure complete sealing.

After these steps of slitting and trimming the web and applying side tapes, the photographic components are mounted, the web is severed transversely at packet-length intervals, tape 20 is folded to bring the two sides of the packet into opposition, and tape 18 is folded and heat laminated to side 14, all by other portions of the apparatus not described here. After manufacture as described, both sides of the packet have the same dimensional response to humidity changes, so that the packet will remain fiat until it is used.

Other embodiments will occur to those skilled in the art and are within the following claim.

What is claimed is:

1. In a process for manufacturing film packets each of which comprises outer walls within which are contained photographic components, the intermediate steps of:

longitudinally cutting a unitary paper web centrally into two strips,

simultaneously with said cutting trimming the lateral margins of said unitary web to cause said two strips to be of identical known width,

3 4 adhering a first pre-creased narrow tape to the slit web References Cited along the resulting central cut, UNITED STATES PATENTS adhering a portion of the width of a second narrow 1 584 450 5/1926 Hager tape to Said Web along one of Said margins, 2:587:685 3/1952 Bergstein 156-259 bringing said strips into opposition to respectively pro- 5 3,250,334 5/1966 perino 5 259 vide said outer walls, and adhering another portion of the width of said second BENJAMIN A. BORCHELT, Primary Examiner p to said other margin- D. BENT, Assistant Examiner 

